JPH05206952A - Low-distortion laser system for amplitude- modulated optical fiber communication use - Google Patents
Low-distortion laser system for amplitude- modulated optical fiber communication useInfo
- Publication number
- JPH05206952A JPH05206952A JP4237632A JP23763292A JPH05206952A JP H05206952 A JPH05206952 A JP H05206952A JP 4237632 A JP4237632 A JP 4237632A JP 23763292 A JP23763292 A JP 23763292A JP H05206952 A JPH05206952 A JP H05206952A
- Authority
- JP
- Japan
- Prior art keywords
- optical
- signal
- information signal
- receiver
- optical fiber
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/25—Arrangements specific to fibre transmission
- H04B10/2507—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion
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- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Optical Communication System (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明はアナログ光伝送システム
に関し、さらに詳しくは、レーザ送信機によって生じる
ひずみ成分を消去する装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an analog optical transmission system, and more particularly to a device for canceling distortion components generated by a laser transmitter.
【０００２】[0002]
【従来の技術】光伝送システムは現在、様々な通信分野
での利用に実現されている。例えば、音声およびデータ
信号の長距離伝送に光ファイバ技術を利用している電話
システムが、現在使用されている。同様に、アナログ信
号およびディジタル信号の両方の伝送に光ファイバ技術
を利用したケーブルテレビ網も、現在稼働している。BACKGROUND OF THE INVENTION Optical transmission systems are currently being implemented for use in various communication fields. For example, telephone systems are currently in use that utilize fiber optic technology for long distance transmission of voice and data signals. Similarly, cable television networks that utilize fiber optic technology for transmitting both analog and digital signals are currently in operation.
【０００３】光伝送網が実現される前は、ケーブルテレ
ビ番組は電気同軸ケーブルで無線周波数（ＲＦ）信号と
して伝送された。光ファイバ伝送システムでは、通信レ
ーザを利用してマルチチャネルテレビ信号を送信する。
ＲＦ信号を用いて光源を変調し、変調された光を光ファ
イバの長さに沿って伝送する。Prior to the realization of optical transmission networks, cable television programs were transmitted as radio frequency (RF) signals over electrical coaxial cables. Fiber optic transmission systems utilize communication lasers to transmit multi-channel television signals.
An RF signal is used to modulate the light source and the modulated light is transmitted along the length of the optical fiber.
【０００４】光伝送システムは、実質的に無制限の帯域
幅やシステム性能の向上などをはじめ、かなりの利点が
ある。しかし、高調波ひずみは、アナログ振幅変調光通
信送信システムの大きな制約になる。このようなひず
み、特に二次ひずみは、信号を光通信システムに送信す
るレーザによって導入される。Optical transmission systems have considerable advantages, including substantially unlimited bandwidth and improved system performance. However, harmonic distortion is a major limitation of analog amplitude modulation optical communication transmission systems. Such distortions, especially second order distortions, are introduced by the laser transmitting the signal to the optical communication system.
【０００５】１９８３年７月１２に発行された米国特許
第４，３９３，５１８号「光通信装置」は、電気的アナ
ログ入力信号を１対の光ファイバを介して２つの分離し
た光信号として受信機に伝送する送信機を含む光伝送シ
ステムを開示している。光信号の片方は、入力信号の正
の部分を表わす。もう一方は、入力信号の負の部分を表
わす。２つの光信号を受信機で結合することによって、
入力信号を表わす電気的アナログ出力信号が、伝送中に
生じたかもしれない偶数調波成分を含むことなく生成さ
れる。受信機は、入力信号を再生するために、差動増幅
器をはじめとする様々な増幅器を必要とする。US Pat. No. 4,393,518, "Optical Communication Device", issued July 12, 1983, receives an electrical analog input signal as two separate optical signals via a pair of optical fibers. Disclosed is an optical transmission system including a transmitter for transmitting to a machine. One of the optical signals represents the positive part of the input signal. The other represents the negative part of the input signal. By combining the two optical signals at the receiver,
An electrical analog output signal representative of the input signal is produced without the even harmonic components that may have occurred during transmission. The receiver requires various amplifiers, including differential amplifiers, to recover the input signal.
【０００６】同一譲受人に譲渡された同時係属出願の
「ひずみを消去する光ファイバ伝送システム」と題する
米国出願第０７／４３６，６１４号は、アナログ入力信
号を１本のファイバで受信機に伝送し、入力信号を反転
したものを別個の並列ファイバで受信機に伝送する構造
を開示している。受信機で信号を結合して、信号の伝送
中に生じた高調波ひずみを解消する。入力信号全体が並
列ファイバの両方を通して伝送されるので、片方のファ
イバが切断された場合でも、品質は低下するが、送信さ
れた情報を復元することができる。[0006] US patent application Ser. No. 07 / 436,614, entitled "Distortion Eliminating Fiber Optic Transmission System," assigned to the same assignee, transmits an analog input signal to a receiver over a single fiber. However, a structure is disclosed in which the inverted input signal is transmitted to the receiver through separate parallel fibers. The receiver combines the signals to eliminate harmonic distortion that occurs during signal transmission. Since the entire input signal is transmitted through both parallel fibers, if one fiber is cut, the transmitted information can be recovered, albeit with reduced quality.
【０００７】[0007]
【発明が解決しようとする課題】上述のひずみ消去構造
は両方とも欠点がある。例えば、並列ファイバを使用す
る必要があるので、伝送網の建設費用が高くなる。ま
た、受信機の設計は幾分複雑になり、実現費用が比較的
高価になる。Both of the strain relief structures described above have drawbacks. For example, the cost of constructing a transmission network is high due to the need to use parallel fibers. Also, the receiver design is somewhat complicated and relatively expensive to implement.
【０００８】振幅変調残留側波帯（ＡＭ−ＶＳＢ）テレ
ビ信号などのようなアナログ信号を伝送する光ファイバ
システムのひずみを緩和する改良システムを提供するこ
とは有益である。本発明はそうした装置を提供する。It would be beneficial to provide an improved system for mitigating distortion in fiber optic systems transmitting analog signals such as amplitude modulated vestigial sideband (AM-VSB) television signals and the like. The present invention provides such a device.
【０００９】[0009]
【課題を解決するための手段】本発明では、アナログ信
号を光ファイバ伝送路で伝送するための装置を提供す
る。第１光搬送波を生成するために半導体レーザなどの
手段を装備する。第１光搬送波を、アナログＡＭ信号な
どの情報信号で変調する。情報信号の位相を反転し、反
転後の情報信号で第２光搬送波を変調する手段を装備す
る。第１光搬送波と同様に、第２光搬送波も半導体レー
ザによって生成することができる。１つの光ファイバ通
信路で伝送するために、両方の搬送波を単独の光信号に
多重化（マルチプレクシング）する手段を装備する。SUMMARY OF THE INVENTION The present invention provides an apparatus for transmitting an analog signal over an optical fiber transmission line. A means such as a semiconductor laser is provided to generate the first optical carrier. The first optical carrier wave is modulated with an information signal such as an analog AM signal. A means for inverting the phase of the information signal and modulating the second optical carrier with the inverted information signal is provided. Like the first optical carrier, the second optical carrier can also be generated by a semiconductor laser. It is equipped with a means for multiplexing both carriers into a single optical signal for transmission on one optical fiber communication path.
【００１０】受信機は、光ファイバ通信路の遠隔端部に
接続されて、多重化光信号を分離（デマルチプレクシン
グ）して情報信号および反転情報信号を復元する手段を
含む。復元された信号を結合して、ひずみを緩和した電
気領域の情報信号を提供する。好適実施例では、この結
合手段は二重検波器平衡光ダイオード対から成る。別の
実施例では、結合手段は、復元された情報信号を受信し
て対応する電気信号を出力する第１光検波器と、復元さ
れた反転情報信号を受信して対応する電気信号を出力す
る第２光検波器と、第１および第２光検波器からの電気
出力を受信し結合する変成器とから成る。The receiver includes means connected to the remote end of the fiber optic channel for demultiplexing the multiplexed optical signal to recover the information signal and the inverted information signal. The reconstructed signals are combined to provide a strain-relaxed electrical domain information signal. In the preferred embodiment, this coupling means comprises a double detector balanced photodiode pair. In another embodiment, the coupling means receives the reconstructed information signal and outputs a corresponding electrical signal, and the first optical detector receives the reconstructed inverted information signal and outputs a corresponding electrical signal. It consists of a second photodetector and a transformer that receives and combines the electrical output from the first and second photodetectors.
【００１１】送信機で使用するマルチプレクサ手段は、
波長分割マルチプレクサから構成することができる。デ
マルチプレクサ手段は、逆方向に作動して波長分割デマ
ルチプレクサとして機能する波長分割マルチプレクサか
ら構成することができる。変調した第１および第２光搬
送波の多重化および分離は、レーザ送信機の波長を相互
に少し離すことによって容易になる。The multiplexer means used in the transmitter is
It can consist of a wavelength division multiplexer. The demultiplexer means may consist of a wavelength division multiplexer operating in the opposite direction and functioning as a wavelength division demultiplexer. Multiplexing and demultiplexing the modulated first and second optical carriers is facilitated by keeping the wavelengths of the laser transmitters slightly separated from each other.
【００１２】[0012]
【実施例】図１は、本発明による送信機を示す。多数の
ＡＭ−ＶＳＢテレビジョン信号を従来のＲＦ変調器１０
によって生成し、ＲＦ信号スプリッタ１２へ入力する。
信号スプリッタ１２はＲＦ信号の２つの経路を提供す
る。第１経路では、信号を位相反転回路１４によって反
転し、線路２１へ出力して、半導体レーザ２２などの光
搬送波発生器の変調に使用する。レーザ２２は、例えば
１．５ミクロンといった所定の波長の光搬送波を出力す
る。位相反転回路１４からのＲＦ信号でレーザ出力を変
調することによって、反転入力信号を光ファイバで伝送
することができる。当業界では周知のごとく、光搬送波
発生器の直接変調または外部変調のどちらでも使用する
ことができる。1 shows a transmitter according to the invention. A large number of AM-VSB television signals are converted to a conventional RF modulator 10
And input to the RF signal splitter 12.
The signal splitter 12 provides two paths for RF signals. In the first path, the signal is inverted by the phase inversion circuit 14, output to the line 21, and used for modulation of the optical carrier generator such as the semiconductor laser 22. The laser 22 outputs an optical carrier having a predetermined wavelength, such as 1.5 microns. By modulating the laser output with the RF signal from the phase inverting circuit 14, the inverting input signal can be transmitted over an optical fiber. As is well known in the art, either direct or external modulation of the optical carrier generator can be used.
【００１３】スプリッタ１２によって提供される第２Ｒ
Ｆ経路では、入力信号の振幅を減衰器１６で必要に応じ
て減衰した後、従来のＲＦ傾斜および位相調整回路１８
で調整することによって、線路１９のＲＦ変調信号出力
の振幅、傾斜、および位相を線路２１の位相反転変調信
号出力と一致させる。線路１９と線路２１の信号の唯一
の相違は、線路２１の信号の位相が、線路１９の信号の
位相と１８０°ずれていることである。Second R provided by splitter 12
In the F path, the amplitude of the input signal is attenuated by the attenuator 16 as necessary, and then the conventional RF tilt and phase adjustment circuit 18
By adjusting the amplitude, slope, and phase of the RF modulation signal output of the line 19 with the phase inversion modulation signal output of the line 21. The only difference between the signals on line 19 and line 21 is that the signal on line 21 is 180 ° out of phase with the signal on line 19.
【００１４】線路１９の調整したＲＦ信号は、レーザ２
０によって発生される光搬送波で伝送することができる
ように、半導体レーザ２０の変調入力に結合する。好適
実施例では、レーザ２０の波長は、レーザ２２の波長か
らわずかに（例えば約２−５ナノメータだけ）ずらし、
従来の波長分割多重化／分割技術を用いてレーザ２０、
２２のそれぞれの搬送波出力を多重化および分割するこ
とができるようにする。The adjusted RF signal on the line 19 is transmitted to the laser 2
0 is coupled to the modulation input of the semiconductor laser 20 so that it can be transmitted on an optical carrier generated by a zero. In the preferred embodiment, the wavelength of laser 20 is slightly offset from the wavelength of laser 22 (eg, by about 2-5 nanometers),
Laser 20 using conventional wavelength division multiplexing / division techniques,
Allows each of the 22 carrier outputs to be multiplexed and split.
【００１５】図１に示す実施例では、レーザ２０、２２
の変調した搬送波出力を、従来の波長分割マルチプレク
サ（ＷＤＭ）２４に入力する。ＷＤＭ２４は２つの変調
搬送波を結合し、単独の光信号として光ファイバ２６に
出力する。信号強度を長距離にわたって維持するため
に、ファイバ２６に沿ってエルビウムファイバ増幅器な
どの光増幅器（図示せず）を１つ以上装備することがで
きる。In the embodiment shown in FIG. 1, the lasers 20, 22 are
The modulated carrier wave output of (1) is input to a conventional wavelength division multiplexer (WDM) 24. The WDM 24 combines the two modulated carriers and outputs them to the optical fiber 26 as a single optical signal. One or more optical amplifiers (not shown), such as erbium fiber amplifiers, may be provided along fiber 26 to maintain signal strength over long distances.
【００１６】図２は、光ファイバで伝送された多重化光
信号の受信機の１つの実施例を示す。光ファイバからの
信号は、逆方向に作動して分割機能を提供する波長分割
マルチプレクサ２８へ入力する。こうして、変調器１０
よって提供された情報を含み、レーザ２０から出力した
変調搬送波は、光ファイバ３０で復元され、また反転情
報を含み、レーザ２２から出力した変調搬送波は、光フ
ァイバ３２で復元される。復元された搬送波の平衡を維
持するために、ファイバ３０と３２は、復元搬送波を受
信するために結合する光検波器の間隔と一致するように
厳密に制御された間隔でひとつに結合することが望まし
い。FIG. 2 illustrates one embodiment of a receiver for multiplexed optical signals transmitted over optical fiber. The signal from the optical fiber enters the wavelength division multiplexer 28 which operates in the opposite direction to provide the division function. Thus, the modulator 10
Thus, the modulated carrier output from the laser 20 containing the provided information is restored in the optical fiber 30 and the inverted carrier output containing the inversion information is output in the optical fiber 32. To maintain the balance of the recovered carrier, the fibers 30 and 32 may be combined together at closely controlled intervals to match the intervals of the photodetectors that combine to receive the recovered carrier. desirable.
【００１７】図２に示す実施例では、ファイバ３０から
の情報信号およびファイバ３２からの反転情報信号を、
二重検波器平衡光ダイオード対３４の光検波器３６、３
８にそれぞれ入力する。ダイオード対３４は、例えば、
エレクトロニクス・レターズ第２５巻１７号１９８９年
８月１７日号１１４４−１１４５頁におけるＭ．マキウ
チらの「平衡光波受信機用の高速モノリシックＧａｉｎ
ＡＳデュアルピンホトダイオード」（M. Makiuchi, et
al, "High-Speed Monolithic GainAs Twin-pinPhotodio
de for Balanced Optical Coherent Receivers", Elect
ronics Letters , 17 August 1989, Vol. 25, No. 17,
pp. 1144-1145）で開示された、平衡ミキサ構造に２つ
のダイオードを組み込んだ高速モノリシック素子から構
成することができる。In the embodiment shown in FIG. 2, the information signal from fiber 30 and the inverted information signal from fiber 32 are
Dual detectors Photodetectors 36, 3 of balanced photodiode pair 34
Input in 8 respectively. The diode pair 34 is, for example,
Electronics Letters Vol. 25, No. 17, August 17, 1989, pages 1144-1145. Makiuchi et al., "High-speed monolithic Gain for balanced lightwave receivers
AS Dual Pin Photodiode "(M. Makiuchi, et
al, "High-Speed Monolithic GainAs Twin-pin Photodio
de for Balanced Optical Coherent Receivers ", Elect
ronics Letters , 17 August 1989, Vol. 25, No. 17,
It can be composed of a high-speed monolithic device incorporating two diodes in a balanced mixer structure disclosed in pp. 1144-1145).
【００１８】差動ホトダイオード３６、３８の対は同一
基板上に作成すると、ホトダイオードの暗電流の同相分
排除能力が高いので、出力の雑音電力をかなり軽減する
ことができるという利点がある。ホトダイオードを共通
基板上に搭載することにより、分離したホトダイオード
を検波に使用した場合に生じる周波数成分の高周波同相
分排除能力も高くなる。よく整合したホトダイオード対
を使用すれば、単独の電子デバイスだけでＲＦ情報信号
を復元することができるので、この適用例では高い費用
効果が得られる。ダイオード対３４は、光信号路３０、
３２からそれぞれえ伝送された情報および反転情報を結
合し、変調器１０から出力された元のＲＦ入力信号を電
気領域でひずみを軽減した状態で復元する。復元された
ＲＦ信号は、電気信号路４０を介して、従来の同軸コネ
クタなどのＲＦ出力端子４２へ出力される。変調した情
報を変調した反転情報と結合することによって、信号の
送信中にレーザまたはその他のコンポーネントによって
導入された偶数調波がダイオード対３４で消去される一
方、所望の情報信号の出力電力は倍加される。When the pair of differential photodiodes 36 and 38 are formed on the same substrate, the common-mode rejection capability of the dark current of the photodiodes is high, so that there is an advantage that the output noise power can be considerably reduced. By mounting the photodiodes on the common substrate, the high frequency common-mode rejection capability of the frequency components generated when the separated photodiodes are used for detection is also increased. The use of a well-matched photodiode pair is cost-effective in this application because the RF information signal can be recovered with only a single electronic device. The diode pair 34 includes an optical signal path 30,
The information and the inverted information respectively transmitted from 32 are combined, and the original RF input signal output from the modulator 10 is restored with distortion reduced in the electric domain. The restored RF signal is output to the RF output terminal 42 such as a conventional coaxial connector via the electric signal path 40. By combining the modulated information with the modulated inverted information, the even harmonics introduced by the laser or other component during transmission of the signal are canceled in diode pair 34, while the output power of the desired information signal is doubled. To be done.
【００１９】図３は、受信機の別の実施例を示す。ここ
では、分離した別個の受光素子５０、５２を用いて、復
元された変調光搬送波をそれに対応する電気信号に変換
する。非反転情報は、従来のＲＦ増幅器５４で増幅した
後、変成器５８の１次側へ入力する。反転情報は、ＲＦ
増幅器５６で増幅した後、変成器５８の１次側へ入力す
る。変成器５８は、反転情報信号と非反転情報信号を従
来の方法で結合し、結合信号を出力する。このとき、偶
数調波は消去され、所望の情報信号の電力は倍加されて
ＲＦ出力端子６０へ出力される。FIG. 3 shows another embodiment of the receiver. Here, the separated modulated light carrier is converted into an electric signal corresponding to the separated light receiving elements 50 and 52. The non-inverted information is amplified by the conventional RF amplifier 54 and then input to the primary side of the transformer 58. Inversion information is RF
After being amplified by the amplifier 56, it is input to the primary side of the transformer 58. The transformer 58 combines the inverted and non-inverted information signals in a conventional manner and outputs a combined signal. At this time, the even harmonics are erased, and the power of the desired information signal is doubled and output to the RF output terminal 60.
【００２０】反転情報信号と非反転情報信号の結合によ
る偶数調波ひずみの消去および出力電力の倍加は、数学
的に表現することができる。例えば、レーザ２０（図
１）はＲＦ入力信号“ＥIN”で変調することができる。
波長分割マルチプレクサ２８によって光ファイバ３０に
出力される信号は、ＥOUT1として、次のように表わすこ
とができる。 ＥOUT1＝Ｋ0 ＋Ｋ1 ＥIN＋Ｋ2 （ＥIN)2 ＋Ｋ3 （ＥIN）3 ＋・・・・ ここでＫ0 は信号のＤＣ成分、ＥINは復元される情報信
号、Ｋ2 （ＥIN）2 は受信信号の二次調波ひずみ成分、
Ｋ3 （ＥIN）3 は３次ひずみ成分であり、以下同様に続
く。Elimination of even harmonic distortion and doubling of output power due to the combination of inverted and non-inverted information signals can be expressed mathematically. For example, laser 20 (FIG. 1) can be modulated with an RF input signal "E IN ".
The signal output to the optical fiber 30 by the wavelength division multiplexer 28 can be represented as E OUT1 as follows. E OUT1 = K 0 + K 1 E IN + K 2 (E IN ) 2 + K 3 (E IN ) 3 + ... where K 0 is the DC component of the signal, E IN is the restored information signal, K 2 ( E IN ) 2 is the second harmonic distortion component of the received signal,
K 3 (E IN ) 3 is the third-order strain component, and so on.
【００２１】レーザ２２に入力されるＲＦ入力信号は位
相がＥINと１８０°ずれており、“−ＥIN”と表わすこ
とができる。したがって、光ファイバ３２に出力される
復元信号ＥOUT2は、次のように表わすことができる。 ＥOUT2＝−Ｋ0 ＋Ｋ1 （−ＥIN）＋Ｋ2 （−ＥIN）2 ＋Ｋ3 （−ＥIN）3 ＋・ ・ これで分かるように、ＥOUT2では奇数次の積は全部負と
なり、偶数次の積は全部正となる。したがって、ＥOUT1
とＥOUT2の大きさが等しく、位相が１８０°ずれている
場合、ＤＢＯＲ３４または変成器５８は信号を結合し、
ＥOUT1からＥOUT2を効果的に引き算するので、全ての偶
数次の成分は消去され、全ての奇数次の成分（復元すべ
き信号ＥINを含む）は強さが倍加される。これにより、
復元されるＲＦ信号の信号レベルが３ｄＢ増加する一
方、障害となる２次調波ひずみ成分は消去される。The RF input signal input to the laser 22 is 180 ° out of phase with E IN and can be represented as "-E IN ". Therefore, the restoration signal E OUT2 output to the optical fiber 32 can be expressed as follows. E OUT2 = -K 0 + K 1 (-E IN ) + K 2 (-E IN ) 2 + K 3 (-E IN ) 3 + ・ ・ As you can see, in E OUT2 all odd-order products are negative, All even-order products are positive. Therefore, E OUT1
And E OUT2 are equal in magnitude and 180 ° out of phase, DBOR 34 or transformer 58 combines the signals,
Effectively subtracting E OUT1 from E OUT2 eliminates all even-order components and doubles the strength of all odd-order components (including the signal E IN to be restored). This allows
While the signal level of the restored RF signal increases by 3 dB, the disturbing second harmonic distortion component is eliminated.
【００２２】図４は、本発明の通信システムの別の実施
例を示す。この装置の送信部は、レーザ２０、２２まで
は図１と同一である。しかしレーザの出力はひとつに多
重化されない。代替法として、別個の出力をそれぞれ別
個の光ファイバ７０、７２でダイオード対３４へ伝送す
る。信号をダイオード対３４によって結合することによ
って、所望の情報を復元しながら、上述のように偶数調
波ひずみを消去する。図４に示した実施例の不利な点
は、送信機から受信機までずっと並列ファイバ伝送路を
維持しなければならないことである。FIG. 4 shows another embodiment of the communication system of the present invention. The transmitter of this device is the same as in FIG. 1 up to the lasers 20 and 22. However, the laser outputs are not multiplexed together. Alternatively, the separate outputs are transmitted to the diode pair 34 on separate optical fibers 70, 72. By combining the signals with diode pairs 34, the even harmonic distortion is canceled as described above while restoring the desired information. A disadvantage of the embodiment shown in FIG. 4 is that the parallel fiber transmission line must be maintained from transmitter to receiver.
【００２３】以上の説明により、本発明が光ファイバで
少ないひずみで信号を伝送する装置を提供するものであ
ることが、理解されたはずである。二重検波器平衡光ダ
イオード対を使用すると、偶数次調波ひずみを消去しな
がら情報信号を復元することが容易になり、有利であ
る。本発明を幾つかの好適実施例に関連して説明した
が、当業者は、請求の範囲に記載する本発明の精神およ
び範囲から逸脱することなく、これに様々な適応や変化
を加えることができることを理解されるだろう。From the above description, it should be understood that the present invention provides an apparatus for transmitting a signal in an optical fiber with little distortion. Advantageously, the use of dual detector balanced photodiode pairs facilitates the restoration of the information signal while eliminating even harmonic distortion. Although the present invention has been described with reference to some preferred embodiments, those skilled in the art can make various adaptations and changes without departing from the spirit and scope of the invention as claimed. You will understand what you can do.
【図１】 図１は本発明による送信機のブロック図で
あり、電気信号路を単線で、光信号路を二重線で示す。FIG. 1 is a block diagram of a transmitter according to the present invention, showing electrical signal paths by single lines and optical signal paths by double lines.
【図２】 図２は本発明による受信機の１実施例を示
すブロック図であり、光信号路を二重線で表わす。FIG. 2 is a block diagram showing an embodiment of a receiver according to the present invention, in which an optical signal path is represented by a double line.
【図３】 図３は本発明による受信機の別の実施例を
示すブロック図であり、光信号路を二重線で表わす。FIG. 3 is a block diagram showing another embodiment of the receiver according to the present invention, in which the optical signal path is represented by a double line.
【図４】 通信信号を二重線で表わす２つの並列光信
号路により二重検波器平衡光ダイオード対に伝送する、
本発明の別の実施例を示すブロック図である。FIG. 4 transmits a communication signal to a dual detector balanced photodiode pair by two parallel optical signal paths represented by double lines,
It is a block diagram which shows another Example of this invention.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 デヴィッド・アール・ヒューバー アメリカ合衆国ペンシルヴァニア州ウォー リントン、カントリー・クラブ・ドライヴ 68 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor David Earl Huber Country Club Drive 68, Warrington, PA, USA
Claims (15)
信する装置において、前記通信装置が、 第１光搬送波を生成する手段と、 前記第１光搬送波をアナログ情報信号で変調する手段
と、 前記アナログ情報信号の位相を反転する手段と、 第２光搬送波を生成する手段と、 前記第２光搬送波を前記反転アナログ情報信号で変調す
る手段と、 前記第１および第２光搬送波を光ファイバ伝送路で伝送
するために単独の光信号に多重化する多重化手段とから
成ることを特徴とする通信装置。1. A device for communicating an analog signal through an optical fiber communication path, wherein the communication device generates a first optical carrier wave, a means for modulating the first optical carrier wave with an analog information signal, and the analog signal. Means for inverting the phase of the information signal, means for generating a second optical carrier, means for modulating the second optical carrier with the inverted analog information signal, and optical fiber transmission lines for the first and second optical carriers. And a multiplexing unit that multiplexes into a single optical signal for transmission by the communication device.
号を分離して、前記情報信号および反転情報信号を復元
する分離手段と、 復元された信号を結合して、前記情報信号を電気領域で
ひずみを軽減した状態で提供する結合手段とから成るこ
とを特徴とする、請求項１記載の通信装置。2. The communication device is further connected to a remote end of the optical fiber communication path, separates the optical signal and restores the information signal and the inverted information signal, and the restored signal. 2. The communication device according to claim 1, further comprising: a coupling means for coupling the information signal and providing the information signal in a state where distortion is reduced in an electric region.
オード対から成ることを特徴とする、請求項２記載の通
信装置。3. The communication device according to claim 2, wherein said coupling means comprises a double detector balanced photodiode pair.
信号を出力する第１光検波器と、 前記復元された反転情報信号を入力し、それに対応する
電気信号を出力する第２光検波器と、 前記第１および第２光検波器からの電気出力を入力し結
合する変成器とから成ることを特徴とする、請求項２記
載の通信装置。4. The first photodetector, wherein the coupling means inputs the restored information signal and outputs an electric signal corresponding to the first information detector, and inputs the restored inverted information signal to an electric signal corresponding to the first optical detector. 3. The communication device according to claim 2, comprising a second optical detector that outputs a signal, and a transformer that inputs and couples the electrical outputs from the first and second optical detectors.
クサから成り、前記分離手段が波長分割デマルチプレク
サから成ることを特徴とする、請求項２ないし４のいづ
れかに記載の通信装置。5. The communication device according to claim 2, wherein the multiplexing means comprises a wavelength division multiplexer and the demultiplexing means comprises a wavelength division demultiplexer.
ザから成り、 前記第２光搬送波生成手段が第２レーザから成り、 変調した第１および第２光搬送波の多重化および分離を
容易にするために、前記第１レーザの波長と前記第２レ
ーザの波長との間にわずかな間隔を置くことを特徴とす
る、請求項１ないし５のいづれかに記載の通信装置。6. The first optical carrier generation means comprises a first laser and the second optical carrier generation means comprises a second laser to facilitate multiplexing and demultiplexing of the modulated first and second optical carriers. In order to do so, a slight distance is provided between the wavelength of the first laser and the wavelength of the second laser, and the communication device according to any one of claims 1 to 5.
が半導体レーザから成ることを特徴とする、請求項１な
いし６のいづれかに記載の通信装置。7. The communication device according to claim 1, wherein the first and second optical carrier wave generation means are semiconductor lasers.
クサから成ることを特徴とする、請求項１記載の通信装
置。8. The communication device according to claim 1, wherein the multiplexing means comprises a wavelength division multiplexer.
から成ることを特徴とする、請求項１ないし８のいづれ
かに記載の通信装置。9. The communication device according to claim 1, wherein the information signal comprises an analog amplitude modulation signal.
および前記情報信号を１８０°移相して伝送する第２光
ファイバからアナログ情報信号を復元する受信機におい
て、前記受信機が、 二重検波器平衡光ダイオード対と、 前記第１光ファイバを前記光受信機の第１検波器に光学
的に結合する手段と、 前記第２光ファイバを前記光受信機の第２検波器に光学
的に結合する手段とから成り、 前記光受信機が、第１光ファイバからの情報信号と第２
光ファイバからの移相情報信号を結合することによっ
て、そこに含まれるひずみ成分を消去し、前記情報信号
を電気領域でひずみレベルを低下して出力することを特
徴とする受信機。10. A receiver for recovering an analog information signal from a first optical fiber for transmitting an information signal and a second optical fiber for transmitting the information signal with a phase shift of 180 °, wherein the receiver is double-detected. -Balanced photodiode pair, means for optically coupling the first optical fiber to a first detector of the optical receiver, and the second optical fiber to a second detector of the optical receiver optically. Means for coupling, wherein the optical receiver comprises an information signal from the first optical fiber and a second signal
A receiver characterized in that a phase shift information signal from an optical fiber is coupled to eliminate a distortion component contained therein, and the information signal is outputted with a reduced distortion level in an electric region.
力信号を受信する手段と、 受信した光入力信号を分離して、前記情報信号を前記第
１光ファイバに提供し、前記移相情報信号を前記第２光
ファイバに提供する分離手段とから成ることを特徴とす
る、請求項１０記載の受信機。11. The receiver further includes means for receiving an optical input signal including the information signal multiplexed with the phase shift information signal, separating the received optical input signal, and outputting the information signal to the first signal. 11. Receiver according to claim 10, characterized in that it comprises a separating means for providing one optical fiber and for providing the phase shift information signal to the second optical fiber.
プレクサから成ることを特徴とする、請求項１１記載の
受信機。12. The receiver according to claim 11, wherein said demultiplexing means comprises an optical wavelength division demultiplexer.
からアナログ情報信号を復元する受信機において、前記
受信機が、 前記ファイバに接続され、前記光入力信号を分離して、
前記情報信号および前記情報信号の反転信号を復元する
分離手段と、 復元された情報信号を復元された反転情報信号と結合し
て、そこに含まれるひずみ成分を消去し、前記情報信号
を電気領域でひずみレベルを低下して出力する結合手段
とから成ることを特徴とする受信機。13. A receiver for recovering an analog information signal from an optical input signal transmitted by an optical fiber, wherein the receiver is connected to the fiber and separates the optical input signal,
Separating means for restoring the information signal and the inverted signal of the information signal, and combining the restored information signal with the restored inverted information signal to eliminate the distortion component contained therein, and the information signal in the electrical domain And a coupling means for reducing the distortion level and outputting.
レクサから成ることを特徴とする、請求項１３記載の受
信機。14. The receiver according to claim 13, wherein said demultiplexing means comprises a wavelength division demultiplexer.
信号を出力する第１光検波器と、 前記復元された反転情報信号を入力し、それに対応する
電気信号を出力する第２光検波器と、 前記第１および第２光検波器からの電気出力を入力し結
合する変成器とから成ることを特徴とする、請求項１３
または１４記載の受信機。15. The first optical detector, wherein the coupling means inputs the restored information signal and outputs an electric signal corresponding to the restored information signal, and inputs the restored inverted information signal to an electric signal corresponding to the first optical detector. 14. A second photodetector for outputting a signal, and a transformer for inputting and coupling the electric outputs from the first and second photodetectors.
Or the receiver according to 14.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/745,539 US5257124A (en) | 1991-08-15 | 1991-08-15 | Low distortion laser system for AM fiber optic communication |
| US745539 | 1996-11-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05206952A true JPH05206952A (en) | 1993-08-13 |
Family
ID=24997111
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4237632A Pending JPH05206952A (en) | 1991-08-15 | 1992-08-14 | Low-distortion laser system for amplitude- modulated optical fiber communication use |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US5257124A (en) |
| EP (1) | EP0528225A3 (en) |
| JP (1) | JPH05206952A (en) |
| CA (1) | CA2075387C (en) |
| MX (1) | MX9204715A (en) |
| NO (1) | NO923164L (en) |
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| JPS6427828A (en) * | 1987-07-23 | 1989-01-30 | Hitachi Metals Ltd | Compression device for tube protection cover |
| JPH01123538A (en) * | 1987-11-07 | 1989-05-16 | Nec Corp | Light balance transmitting circuit |
| JPH01220533A (en) * | 1988-02-27 | 1989-09-04 | Nec Corp | Optical transmitter |
-
1991
- 1991-08-15 US US07/745,539 patent/US5257124A/en not_active Expired - Lifetime
-
1992
- 1992-07-30 EP EP19920112971 patent/EP0528225A3/en not_active Withdrawn
- 1992-08-06 CA CA002075387A patent/CA2075387C/en not_active Expired - Fee Related
- 1992-08-13 NO NO92923164A patent/NO923164L/en unknown
- 1992-08-14 MX MX9204715A patent/MX9204715A/en unknown
- 1992-08-14 JP JP4237632A patent/JPH05206952A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58181343A (en) * | 1982-04-16 | 1983-10-24 | Nippon Denso Co Ltd | Optical signal transmission circuit |
| JPH0382230A (en) * | 1989-08-25 | 1991-04-08 | Toshiba Corp | Optical transmission system and optical transmitter |
| JPH03132227A (en) * | 1989-10-18 | 1991-06-05 | Matsushita Electric Ind Co Ltd | Rf multiple signal light transmission system |
| JPH03173232A (en) * | 1989-11-15 | 1991-07-26 | General Instr Corp | Distortion erasing method of optical fiber transmission system, device and system therefor |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005050884A1 (en) * | 2003-11-20 | 2005-06-02 | Nippon Telegraph And Telephone Corporation | Wavelength multiplex transmission system |
| US7248803B2 (en) | 2003-11-20 | 2007-07-24 | Nippon Telegraph And Telephone Corporation | Wavelength multiplex transmission systems |
| WO2006009269A1 (en) * | 2004-07-20 | 2006-01-26 | National Institute Of Information And Communications Technology, Incorporated Administrative Agency | Frequency shift keying demodulator |
| US8170422B2 (en) | 2004-07-20 | 2012-05-01 | National Institute Of Information And Communications Technology, Incorporated Administrative Agency | Frequency shift keying demodulator |
| WO2006031014A1 (en) * | 2004-09-16 | 2006-03-23 | Ls Cable Ltd. | Optical transmission system using ossb-modulation and signal transmission method |
| JP2006115524A (en) * | 2004-09-21 | 2006-04-27 | Emcore Corp | Method and apparatus for distortion control for optical transmitter |
Also Published As
| Publication number | Publication date |
|---|---|
| MX9204715A (en) | 1993-02-01 |
| US5257124A (en) | 1993-10-26 |
| CA2075387C (en) | 2003-04-08 |
| NO923164L (en) | 1993-02-16 |
| EP0528225A2 (en) | 1993-02-24 |
| EP0528225A3 (en) | 1993-08-25 |
| NO923164D0 (en) | 1992-08-13 |
| CA2075387A1 (en) | 1993-02-16 |
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